By weight, water constitutes the largest portion of a food animal. The amount of water is usually found in the range 70-80%. Part of this water is found in free form while the rest is bound to proteins, especially myofibrillar proteins, through charged and polar groups. The amount of immobilized water depends on the available space within the myofibrillar structure and, in fact, the volume of myofibrils is decisive to the water-binding capacity of the muscle. Some variations exist between muscles due to the types of muscle fibers, degree of fiber contraction and pre-rigor plI. The water retention also depends on the ultimate pH reached after rigor mortis and this will have a strong influence on the activity of muscle enzymes involved in proteolysis and lipolysis during ageing and further processing. Variations may be also expected between animal species and age at slaughter.
From the time an animal is slaughtered, its carcass begins to lose water, which results in a shrinkage, or weight loss, of the meat. This weight loss, which begins at slaughtering, continues through the refrigeration and butchering steps in meat processing, and also continues during cooking. The weight loss results in the meat generally becoming tougher, there is less amount of product to sell, and that product is of diminished quality. Furthermore, cooking shrinkage results in a still smaller amount of cooked meat served for ultimate consumption.
Before reaching the consumer, most foods are processed in some way. For example, meat products are separated from unusable or undesirable elements or components, ground or chopped, mixed or blended, and can be frozen for distribution.
Meat treatments are well known for enhancing the appearance and flavor of meat products for use by consumers. For example, the pH of a meat carcass immediately decreases due to glycolysis by muscle tissues. Accordingly, one of the most common meat treatments consists of using a phosphate to increase the pH (U.S. Pat. No. 4,818,528). The pH can also be increased to prevent microbes from contaminating the meat. See, for example, U.S. Pat. Nos. 6,899,908 and 6,713,108. This process returns the meat to a more pre-slaughter state. However, many such treatments result in diminishing water retention, and can also result in meat having, an “over processed” look and flavor.
The application of sodium carbonate in a vacuum is another method of treating meat. Sodium carbonate, like phosphates, serves as a pH buffer (U.S. Pat. No. 5,939,112). However, sodium carbonate has been described as being less effective for enhancing water retention in meat than other treatments such as alkali silicates (U.S. Pat. No. 7,001,630).
In the meat industry, it is desirable for meat products to retain moisture during storage and cooking. This is true for all meat products, such as pork, lamb, beef and poultry, which may contain as much as 75% moisture. In addition to retention of natural moisture, i.e., water and fat, it is desirable that the meat retain any moisture added during meat processing. The ability to maintain total moisture enhances the ability of the meat products to retain flavor, and also enhances juiciness and tenderness of the cooked product. Loss of liquid reflects loss of water and liquid fat, which collectively make up the juice of the meat. Shrinkage during cooking is caused by a loss of liquid, and can be measured by weight loss of the meat. In addition, the overall appearance of the meat is not enhanced and quality is diminished when excessive moisture is lost during cooking. For example, untreated poultry fibers often appear dry and stringy after cooking, whereas treated poultry fibers exhibit a more natural looking appearance.
Phosphates are also commonly used in the meat industry to raise the pH of the meat to increase the water holding capacity of the protein fibers. One such process is described in U.S. Pat. No. 4,818,528 that teaches treating and packaging fresh meat to retain the fresh meat color and to postpone microbial deterioration and spoilage. However, phosphate treatments can have a tendency to diminish texture, appearance and flavor of meat treatments. Meats that have undergone phosphate treatments are commonly known in the meat industry as being “over-processed” or having a “processed” look and/or taste.
Other meat treatments are also known in the industry. For example, published U.S. Patent Application No. 2004/0219283 describes the use of trehalose to treat uncooked meat in order to decrease shrinkage during cooking. The use of sodium bicarbonate in the meat treatment industry has also been previously reported. For example, U.S. Pat. No. 7,060,309 describes the use of sodium bicarbonate under a vacuum to reduce the number of holes in subsequently cooked meat. In addition, U.S. Pat. No. 6,020,012 describes the use of sodium bicarbonate as an injectable treatment to reduce the rate of pH decline.
Sodium carbonate has been described before for use in different industries, such as water softening, etc. In most instances, it is used to buffer the pH of liquid foodstuffs. Sodium carbonate has also been described for use in the meat industry as one of many useful alkalis. In U.S. Pat. No. 5,939,112, a composition optionally containing sodium carbonate at a pH of 5 to 10, and preferably from 6.5 to 8.5, is described for treating meat at a temperature of 20° C. or lower. Higher temperatures and pH are discouraged because they would toughen the meat.
Accordingly, there remains a need to provide methods for processing meat to enhance moisture and flavor retention using phosphate free compositions. The present invention involves processing meat with a liquid brine composition containing salt and sodium carbonate (as well as optional ingredients) at a pH in the range from 10.1 to 11.3.